Vehicle disk brakes employ a rotor surrounding each wheel hub as a friction surface that is engaged by calipers to apply a braking force to a wheel mounted on the wheel hub. These rotors become worn with prolonged use and periodically need to be replaced. When the rotor has become so worn as to require replacement, it is frequently found to be affixed to the wheel hub by dirt and corrosion, making removal of the rotor difficult. A device for mechanically forcing the rotor from the hub is desirable to facilitate removal.
A classic device for removing an object from a shaft is known as a gear puller, which employs two or more arm members that engage a shaft-mounted gear, and an extendible member that engages the shaft. A screw mechanism forces the extendible member toward the gear, and the engagement of the arm members with the gear causes the gear to be forced to the end of the shaft. If the extendible member has a terminal portion with a diameter less than that of the shaft, the gear can be further forced to remove it from the shaft.
One early mechanical wheel puller is taught in U.S. Pat. No. 3,337,943, which teaches a wheel puller having an overall configuration similar to a classical gear puller, but with a hydraulic piston replacing the screw mechanism. The puller has a hydraulic cylinder with an extendible ram and two pivotably attached and opposed claws. In use, the claws are placed behind the wheel, pulley, or similar shaft-mounted object, while the ram is placed against the end of the shaft. The cylinder is then operated to extend the ram toward the ends of the claws, which causes the claws to forcibly engage and remove the wheel or pulley from the shaft. Similar hydraulic pullers are taught in U.S. Pat. Nos. 1,581,057; 1,777,616; 2,003,648; 2,003,756; 2,262,969; 5,159,743; 5,167,057; 5,233,740; 5,419,027; and 5,896,639. These devices require considerable care and effort in correctly placing the arm members to engage the shaft-mounted object as the extendible member is extended. Correct placement of the arm members is further complicated in the case of vehicle brake rotors, since these rotors typically are recessed in a wheel well of the vehicle and there is typically surrounding structure, such as brake calipers, that severely limits access to the rotor.
U.S. Pat. Nos. 3,069,761 and 3,908,258 teach hydraulic pullers with arm members which have adjustment mechanisms to assist in placing the arm members into the proper position for engagement with a shaft-mounted object. However, in both devices the adjustment mechanism is bulky and would not appear to be suitable for use where clearances are limited, such as for use removing vehicle brake rotors.
Thus, there is a need for a puller which facilitates placement of the pivoting members with respect to the rotor, even in situations where clearance about the rotor is limited.